Dane Salazar

Cerebral desaturation events during shoulder arthroscopy in the beach chair position: patient risk factors and neurocognitive effects.

BACKGROUND Patients undergoing shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications due to cerebral ischemia. We sought to define the incidence, patient risk factors, and clinical sequelae of intraoperative cerebral desaturation events. METHODS Regional cerebral tissue oxygen saturation (rSO2) was monitored intra-operatively using near-infrared spectroscopy (NIRS) on 50 consecutive patients. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered to each patient pre- and postoperatively. Intra-operative decreases in rSO2 of 20% or greater were defined as cerebral desaturation events (CDE). The association between intraoperative CDE and postoperative cognitive decline was assessed. RESULTS The incidence of intraoperative CDE in our series was 18% (9/50). Increased body mass index (BMI) was found to have a statistically significant association with intraoperative CDE (mean BMI 37.32 vs 28.59, P < .0001). There was no statistical significance in pre- vs postoperative RBANS either in composite scores or any of the sub-indices in either group. CONCLUSION The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with NIRS allows prompt identification and treatment of decreased cerebral perfusion decreasing the risk of this event. Increased BMI was found to be a statistically significant patient risk factor for the development of intra-operative CDE. The transient intra-operative CDEs were not associated with postoperative cognitive dysfunction in our patient series. We believe protocols aimed at detecting and reversing CDE minimize the risk of neurocognitive dysfunction and improve patient safety.

Cerebral Desaturation During Shoulder Arthroscopy: A Prospective Observational Study

BackgroundPatients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia.Questions/purposesWe sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs.MethodsRegional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs.ResultsThe incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes).ConclusionsThe degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.Level of EvidenceLevel III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in beach chair position.

The aim of this prospective cohort study was to investigate the effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in the beach chair position. Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. The head of each subject was manipulated by the examiner and sequentially positioned for 45 seconds in terminal flexion, extension, bilateral rotation, and bilateral lateral bending. Decreases in rSO2 of 20% or greater from baseline were defined as a cerebral desaturation event (CDE). The association between head and neck position and cerebral perfusion was assessed. Eight percent of patients (4/51) experienced CDE during head and neck positioning. Body mass index was found to be a risk factor for CDE (p = .05). When comparing preoperative baseline rSO2 to intraoperative supine and intraoperative upright rSO2, there was no significant decrease in saturation levels for any of the six tested positions. Frequent intraoperative evaluations of the head and neck position as well as careful preoperative positioning may reduce the risk of position-related complications in patients undergoing elective shoulder arthroscopy in the beach chair position. In this studys patient population, however, head and neck position was not found to cause significant cerebral desaturation for the time period tested compared to preoperative baselines.

Results of a Near-Peer Musculoskeletal Medicine Curriculum for Senior Medical Students Interested in Orthopedic Surgery

INTRODUCTION It has been previously demonstrated that medical students do not achieve an adequate musculoskeletal knowledge base on graduation from American medical schools. Several curriculums have been developed to address this measured deficit. Students entering orthopedic surgery residencies have a better musculoskeletal knowledge foundation than their peers but still fail to achieve an acceptable level of proficiency on graduation from medical school. METHODS Fourth-year medical students participating in senior elective rotations in orthopedic surgery over a 2-year period were given a series of lectures developed and presented by post graduate year 3 orthopedic surgery residents. Students completed a validated musculoskeletal competency examination and a survey following the conclusion of their experience, evaluating the effect of this curriculum. RESULTS A total of 71 students over 2 years participated in the near-peer curriculum, with all students completing the validated test. The mean score for the students was 83.6%. Of the 71 students, 60 (84.5%) scored more than the previously published passing rate of 73.1%. There was no correlation identified with the mean test scores and the number of previous orthopedic surgery rotations. From the survey, 96% of the students rated the near-peer curriculum as appropriate for their level, whereas 75% noted that their own medical schools musculoskeletal curriculum was too advanced for their level of training. CONCLUSION A series of lectures was developed by midlevel orthopedic residents for students interested in pursuing a career in orthopedic surgery. After participation in the curriculum, students scored 30-percentage points higher than a previously published test. This study demonstrates that a resident-initiated, near-peer curriculum increases the fundamental knowledge level of students entering orthopedic surgery. An added benefit appeared to be the skills obtained by the residents who created and delivered the lecture series.

Total shoulder arthroplasty in patients with a B2 glenoid addressed with corrective reaming

BACKGROUND This study describes the short-term functional and radiographic outcomes after total shoulder arthroplasty (TSA) in shoulders with a B2 glenoid deformity addressed with corrective reaming. METHODS We conducted a retrospective series of consecutive patients who underwent TSA with a Walch B2 glenoid quantified by computed tomography scan. All glenoid deformities were addressed using partially corrective glenoid reaming. Radiographic and functional outcome measures, including scores on the visual analog scale for pain, American Shoulder and Elbow Standardized Shoulder Assessment, and Simple Shoulder Test were collected. RESULTS Functional outcome scores were available for 59 of 92 eligible subjects (64%) at a mean of 50 months. The mean preoperative retroversion measured 18° (range, -1° to 36°), superior inclination was 8° (range, -11° to 27°), and posterior subluxation was 67% (range, 39%-91%). Mean visual analog scale improved from 7.4 to 1.4, the American Shoulder and Elbow Shoulder Standardized Assessment improved from 35.4 to 84.3, and the SST improved from 4.5 to 9.1. Radiographs were evaluated at a mean of 31 months: 38 had no glenoid radiolucent lines, 13 glenoids had grade 1, 2 had grade 2, and 5 had grade 3 lucencies. There was no difference in the rate of progression of glenoid radiolucencies between shoulders with a preoperative glenoid version of ≤20° (27.8%) compared with glenoids with >20° of retroversion (22.7%, P = .670). No shoulders were revised due to glenoid loosening or instability. CONCLUSION TSA with partial corrective glenoid reaming in selected shoulders with a B2 glenoid deformity resulted in excellent functional and radiographic outcomes at short-term follow-up, with a low risk of revision surgery.

Platelet-rich plasma and the shoulder: clinical indications and outcomes

Purpose of ReviewThe orthopedic community has seen a rapid rise in the clinical use of platelet-rich plasma (PRP) in the management of shoulder pathologies over the past decade. The purpose of this paper is to review the current literature regarding the indications and outcomes of PRP for the surgical and non-surgical management of common shoulder pathologies, including rotator cuff tears.Recent FindingsMultiple studies have been published recently regarding the use of PRP for the operative and non-operative treatment of rotator cuff tears. There has been less research published on the use of PRP in the management of other conditions of the shoulder. Despite attempts to standardize and classify PRP formulations, there remains great variation in the inter- and intra-subjection composition, preparation, and administration techniques of PRP, limiting the conclusions that can be drawn regarding the utility and effectiveness of this biologic treatment as reported by Mazzocca et al. (J Bone Joint Surg Am. 94(4):308–16, 2012).SummaryRecent literature has shown equivocal to minor benefit of PRP use for shoulder pain, function, and healing. While few complications have been reported and PRP administration appears to carry little risk to the patient, the body of literature is currently inconclusive regarding the clinical benefit and cost-effectiveness of PRP in the treatment of shoulder pathology. As for PRP use specifically as an adjunct to surgical rotator cuff repairs, there is no clear consensus on its effectiveness in either clinical or structural outcomes. To further delineate the efficacy of PRP for shoulder pathology, it is essential that more double-blinded, randomized controlled investigations with large sample sizes and standardized PRP preparations be performed.

Investigation of Cerebral Desaturation Events during Shoulder Arthroscopy in the Beach Chair Position

The beach chair position (BCP) is commonly used position in upper extremity surgery. Although there are many advantages to surgery in this position, there are also potential drawbacks and described complications including devastating neurologic outcomes. The etiology of these complications is postulated to be due to the gravitational effects of the seated position leading to cerebral hypoperfusion. We review the current literature on intraoperative cerebral monitoring and neurocognitive complications with shoulder surgery performed in the BCP. A previous systematic review estimated the incidence of neurocognitive complications after surgery in the BCP to be 0.004%. However, the true incidence is unknown and is likely much more common. Reports of neurologic complications have revealed a need for heightened vigilance, alternative anesthesia techniques, and improved monitoring. Methods for monitoring have included near-infrared spectroscopy, a measurement of cerebral oximetry shown to reliably detect cerebral hypoperfusion. In this literature review, we sought to update the incidence of intraoperative cerebral desaturation events (CDEs) to investigate the relationship of CDEs to neurocognitive complications and to review recent reported cases of neurocognitive complications. Existing literature suggest that accurate intraoperativemonitoring of cerebral perfusion may improve patient safety. The beach chair position (BCP) is commonly used position in upper extremity surgery. Compared with the lateral decubitus position, the BCP provides anatomic positioning of the shoulder, reduces risk of brachial plexus injury, and improves airway access.1 Although there are many advantages to surgery in this position, there are also potential drawbacks and described complications with semiupright positioning. Devastating neurologic outcomes have been reported, including stroke, brain death, vision loss, and death.1,2 The etiology of these complications is speculative but is postulated to be due at least in part to a hydrostatic gradient between the heart and the brain created by the Dane H. Salazar, MD William J. Davis, BS